Package com.inductiveautomation.ignition.common.sqltags.history.cache

Class TagHistoryCache

java.lang.Object

com.inductiveautomation.ignition.common.sqltags.history.cache.TagHistoryCache

public class TagHistoryCache
extends java.lang.Object

A cache system for SQLTags History data. It is currently available as a singleton, but for 3rd party use should be instantiated.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	TagHistoryCache.TimeAlteredParams	Parameters with a different time range, and a return size adjusted accordingly.

Constructor Summary

Constructors

Constructor	Description
TagHistoryCache()
TagHistoryCache(boolean enabled, CachePolicy policy)

Method Summary

Modifier and Type	Method	Description
void	clear()	Clears all cached data.
protected boolean	createRoomFor(CacheBucket bucket)	Used when inserting new buckets, tries to eject lower relevency buckets in order to make room.
protected org.apache.log4j.Logger	getBucketLogger()
long	getCurrentMemorySize()
static TagHistoryCache	getInstance()
protected org.apache.log4j.Logger	getLogger()
CachePolicy	getPolicy()
protected double	getWindowSize(TagHistoryQueryParams params)	Returns the window size for the query, or 1/0/-1 if the query mode isn't fixed results.
protected boolean	hasRoomFor(int size)
boolean	isEnabled()
Dataset	query(TagHistoryQueryProvider backingProvider, TagHistoryQueryParams queryParams)
boolean	registerBucket(CacheBucket bucket)	Inserts a bucket into the cache.
static void	reset()	Clears the internal instance, causing all of the cached data to be lost.
void	setEnabled(boolean value)
void	setPolicy(CachePolicy policy)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TagHistoryCache

public TagHistoryCache()

TagHistoryCache

public TagHistoryCache(boolean enabled,
                       CachePolicy policy)

Method Detail

getInstance

public static TagHistoryCache getInstance()

reset

public static void reset()

Clears the internal instance, causing all of the cached data to be lost.

clear

public void clear()

Clears all cached data.

isEnabled

public boolean isEnabled()

setEnabled

public void setEnabled(boolean value)

getPolicy

public CachePolicy getPolicy()

setPolicy

public void setPolicy(CachePolicy policy)

getLogger

protected org.apache.log4j.Logger getLogger()

getBucketLogger

protected org.apache.log4j.Logger getBucketLogger()

getWindowSize

protected double getWindowSize(TagHistoryQueryParams params)

Returns the window size for the query, or 1/0/-1 if the query mode isn't fixed results.

getCurrentMemorySize

public long getCurrentMemorySize()

hasRoomFor

protected boolean hasRoomFor(int size)

createRoomFor

protected boolean createRoomFor(CacheBucket bucket)

Used when inserting new buckets, tries to eject lower relevency buckets in order to make room. If there is already enough room, doesn't eject anything.

query

public Dataset query(TagHistoryQueryProvider backingProvider,
                     TagHistoryQueryParams queryParams)
              throws java.lang.Exception

Throws:

java.lang.Exception

registerBucket

public boolean registerBucket(CacheBucket bucket)

Inserts a bucket into the cache.

Returns:

false if there isn't enough room for the bucket's data. This means the bucket should discard its data and be provisional.